Thermocompressor



J. M LEAN Jan. 3, 1939.

THERMOCOMPRES S OR Filed Aug. 15, 1955 :N yENToR v Jo/m AMacliearz Hi5ATTORNEY.

Patented Jan. 3, 193? UNITED STATES THEBMQGOMP'BESSOR unclean. Hampton,N. 1., asalgnor Ingeraoll-Rand Company, Jersey City, N. J a

JohnA.

corporation of New Jersey Alipllcation Al 15, 1935, Serial No. 36, 71

2 Claims. (Cl. 23-111) My invention relates to improvements intheme-compressors, and particularly thermocompressors of the steam-jetbooster type.

An object of the invention is to provide a steam-jet booster soconstructed that the capacity and ratio of compression can be variedaccording to working conditions, by adjustment of the distance betweenthe jet and the throat of the Venturi tube.

Another object is to construct a convergentdivergent passage or venturiout of simple ele-- ments.

These and other objects of the invention are set forth in the ensuingdescription and the novel features are pointed out in the appendedclaims. While I show and disclose herein a preferred embodiment of theinvention, I may, nevertheless, vary the details of construction withoutdeparting from the principle of the invention or exceeding its spiritand scope.

0n the drawing the figure shows a steam-jet booster according to thisinvention, in longitudinal section.

The numeral I indicates a tubular ejector casing having an inlet 2 atone end for the admission of fluid to be displaced and compressed. Inpractice this ejector may be mounted upon a vessel called an evaporatorin which a liquid refrigerant is cooled by converting it partly intovapor, which passes out of the evaporator and through the inlet opening2 into the casing l. The end of the casing l adjacent the inlet 2 ismade so that it is open when the casing is finished and at said end is asteam chest I connected to a steam supply pipe I. This end of the casingis closed by a mounting plate 5 which is between the casing and steamchest 3, both the plate andthe chest being held removably in place byany suitable means. The plate 5 supports a number of steam nozzles 6which may be arranged in a circular row. When steam is discharged fromthe nozzles it creates a partial vacuum in the evaporator below theinlet 2 and draws the vapor out of the evaporator, impelling it throughthe easing l to the condenser (not shown) where both the steam and vaporare liquefied.

Within the casing is a regulating member I of varying cross section,being thickest near the opening 2 and of smallest diameter adjacent itsopposite extremity. Amxed to the plate 5 is a guide 8 which projectsinto the member I and on which the member can slide when it is moved. Atthe delivery end the casing l is bolted to a spider 9, interposedbetween the casing and the discharge conduit leading to the condenser,and

at the center of the element I and enclosed within the casing is ahollow boss II, the end of which engages slidably with the member illand it is amxed within this member to the movable extremity of a sylphonii, the other end of which p is secured to the spider 9. All the movingparts are, therefore, enclosed in the casing and no seala ing devicesare necessary to prevent leakage therearound.

The sylphon is a therrnally-responsive device connected to move themember 1 as a tempera-- ture aflecting the operation of the compressorvaries. In the form shown, the sylphon is shielded from the fluid in thecasing by a boss "I and receives an expansible liquid connected to beinfluenced by the temperature of the contents of a pipe I! in which ismounted a bulb ll connected by means of a piece of tubing IS with thesylphon I! through a passage It in one of the legs of the spider 9.

When the ejector is mounted upon the evaporator of a refrigeratingdevice the conduit ll may be the'member whichcarries off from the evaporator the refrigerant after it has been cooled an thus the-position ofthe member 1 will be varied according to the temperature of the chilledrefrigerant flowing through the conduit IS.

The member I is of stream-line form being rounded at the end I! whichengages the guide 8. Adjacent this end is a cylindrical section l8,beyond which the member 1 tapers as shown at I! to the shank H. Theannular space or throat 2' around the section I! is of courseunalterable in size. The external surface of the member I and theinternal surface of the casing I defines the venturi into which the jets8 discharge.

The sylphon I! as it expands and contracts will move the member I,causing it to slide on the guide 8 and causing the stem II at the otherend to slide in the bearing of the projection Hi. When this member movesto the left the Venturi throat is moved closer to the jets whichincreases the ratio of compression capable of being developedv by thebooster. Such a characteristic is in accordance with well knownprinciples, and consequently the compressor can operate against agreater back pressure. When the member moves to the right the Venturithroat is moved away from the jets and the back pressure against whichthe compressor can work is decreased; Therefore, if the temperature ofthe cooled refrigerant in the conduit It should drop the member 1 willmove away from the nomles 8 to cut down both porthat is forced throughthe casing I to the condenser, and when the temperature rises theregulator I will be moved in the opposite direction to increase theratio of compression and to 7 permit more steam and vapor to the casing.

In the ordinary type of steam jet ejector with a relatively constantratio of compression and vapor handling capacity there is a limitedrange of satisfactory operation. When operating in connection with anevaporator, at low loads, heat wthrough (vapor) may be removed at sogreat a rate as to result in freezing the refrigerant unless somemethod, such as by-passing, is resorted to. At high loads the pressurein the condenser may increase to a point where it "breaks back throughthe ejector and increases the pressure in the evaporator to a pointwhere refrigeration ceases.

With a movable Venturi throat as described the satisfactory upper andlower limits of the range of the ejector are materially extended bycontrol of the operating characteristics of the compressor. v

This mode of operation enables the ejector to regulate the action of therefrigerating device as required because when the load or demand forrefrigerating effect is highest the temperature of the refrigerant inthe conduit II and the back pressure in the condenser will be relativelyhigh, and the fluid in the bulb I4, tube 'II and sylphon I2 will forcethe member] to the left. The steam jets then have a higher ratio ofcompression and capacity and can extract the maximum amount of vaporfrom the evaporator and force it through the casing. On the other handwhen the load drops. the temperature of the refrigerant returning to theevaporator will be lower and the temperature of the refrigerant afterbeing chilled in the evaporator will be correspondingly less. Likewisethe back pressure in the casing I from the condenser is diminished.Hence the influence of the temperature of the contents of the flue I3will be to enable the sylphon I2 to contract, resulting in a movement ofthe member I to the right. This action results in less vapor at a lowerpressure being forced through the space 20 and therefore less isextracted from the evaporator.

Hence there is less cooling of the refrigerant in the evaporator so thata minimum temperature can be selected. The refrigerant never becomescooler than this minimum temperature and danger of freezing is thusobviated.

The element I is so positioned with respect to the nozzles I thatmovement to the left can never have an obsructing or throttling effect,and because of the parallel walls ofthe casing I the Venturithroat isconstant in area irrespective of movement to the right or left.

with the foregoing construction the capacity of the booster is alwaysadjusted to meet the demands for refrigeration, reducing the amount ofvapor when the load on the system drops and increasing the amountremoved so as to extract a maximum amount of heat from the refrigerantin the evaporator when the load is full. The general design of theevacuatoris quite simple, as will be perceived, and it is certain inoperation and not liable to get out of order.

I claim:

1. A compressor including a parallel walled cas. ing having an inlet atone end and one or more discharge nozzles therein adjacent the inlet, aregulator member in said casing, said member being elongated in shapeand decreasing in diameter away from said nozzles, a guide on which oneend of said member is slidably mounted, said member having a stem at theother end, a hollow projection mounted in the casing slidably engagingsaid stem, and means enclosed within the casing and subject to externalconditions to adjust the position of said member.

2. A compressor including a cylindrical casing having an inlet andoutlet and one or more discharge nozzles at one end, a venturi formingmember in the casing decreasing in diameter toward said outlet, saidmember having a rounded end presented to said nozzles and having aportion of constant diameter adjacent said end and means for slidablymounting the end of said member adjacent said nozzles, said memberhavi'ng a guide stem at the opposite end, means carrying a hollowprojection slidably receiving said stem, a sylphon in said projectionconnected to said stem, and a thermally responsive connection betweensaid sylphon and the exterior of the casing.

JOHN A. MAOLEAN.

